ABSITE-Infection Flashcards
MC organism in SSI
Staph aureus
MC organism in VAP and nosocomial PNA
Staph aureus
Orgs cause toxic shock syndrome?
Staph. aureus, Strep. pyogenes - exotoxin
Orgnism responsible for scalded skin syndrome
Staph aureus
What organisms exude an exoslime biofilm?
S. aureus and S. epidermidis
What enables Staph aureus to be resistent to PCNs?
beta lactamase
How do you treat S. aureas resistant to PCNs?
Anti-staph PCN: e.g. oxacillin, dicloxacillin
What makes MRSA resistant to methicillin?
Th ePCN binding protein has been altered
What % of pop are carriers of MRSA?
20%
What prevalent Staph is coag-? Coag+?
Coag-: S. epidermidis. Coag+S. aureus
MC organism inline infections and catheter-related blood stream infections?
S. epidermidis
What org. is the most frequent contaminant in blood cultures?
S. epidermidis
What infections does Strep pneumoniae cause?
PNA, bacteremia, septic arthritis, endocarditis, cellulitis
Give MC organisms responsible for necrotizing fasciitis
Strep pyogenes
MC org involved in endocarditis
Strep sanguinous
Bugs that cause endocarditis
Strep -viridans, -bovis, -sanguinous, -mitis
Enterococcus faecalis is resistant to what class of abx?
cephalosporins
What % of population has Enterococcus in the gut?
95%
What infections are associated with Enterococcus
UTI, bacteremia, endocarditis, diverticulitis
What causes VRE to be resistant to vancomycin?
Mutation in cell wall binding protein
Are Clostridia aerobic or anaerobic?
Anaerobic
Is Clostridium difficile ever a normal org of the colon?
Yes. 5% are carriers
What org causes gas gangrene and emphesematous cholecystitis?
Glostridium perfringens
What org causes tetanus?
Clostridium tetani
What infections do Corynebacteria cause?
Endocarditis, line infections, cellulitis, granulomatous mastitis
MC organism in gut
Bacteroides fragilis
MC anaerobe in gut
Bacteroides fragilis
MC organism in anaerobic peritoneal infections
Bacteroides fragilis
MC facultative GNR in gut
E. coli
MC organism in UTI
E. coli - 90%
MC org in biliary tract infec (cholangitis)
E. coli
MC org in pyogenic liver abscesses
E. coli
What E. coli type causes food poisoning or HUS?
O157:H7
MC org in struvite nephrolithiasis
Proteus mirabilis
What org produces urease?
Proteus mirabilis
MC lung infection w/ cystic fibrosis?
Pseudomonas aeruginosa
MC organism in burn wound infections?
Pseudomonas aeruginosa
MC colonizer of indwelling catheters?
Pseudomonas aeruginosa
What org produces an alginate mucoid layer?
Pseudomonas aeruginosa
Why is Pseudomonas aeruginosa difficult to treat?
Low abx susceptibility and can undergo acquired resistance during abx tx.
What is the best treatment for Acinetobacter baumannii?
Carbapenems
What org frequently colonizes ETT, trachs and central lines?
Stenotrophomonas maltophilia
Why is Stenotrophomonas maltophilia difficult to treat?
Naturally resistant to many abx, including carbapenems
What org is a contraindication to lung transplant in some centers?
Burkholderia cepacia
What infection is associated with PNA in COPD pts?
Moraxella catarrhalis
Give # of org and classes of org in: stomach
Almost sterile, few GPCs, some yeast
Give # of org and classes of org in: proximal small bowel
10^5 bacteria, mostly GPCs
Give # of org and classes of org in: distal small bowel
10^7 bacteria, GPCs, GPRs, GNRs
Give # of org and classes of org in: colon
10^11 bacteria, 99% anaerobes, few GNRs and GPCs
MC bacterial class (e.g. aerobes, anaerobes) in GI tract
Anaerobes (e.g. bacteroides, and Clostridium)
MC org overall in GI tract
Bacteroides fragilis
MC anaerobe in colon
Bacteroides fragilis (30%)
Anaerobes outnumber aerobic bacteria in what proportion?
1000:01:00
Why do anaerobes require a low O2 environment?
They lack superoxide dismutase and catalase - vulnerable to reactive O2 species
What is the most potent stimulant for TNF-alpha release
Lpid A in LPS (endotoxin) from GNR
MC time frame for atelectasis
POD 1-2
MC time frame for UTI
POD 3-5
MC time frame for DVT
POD 4-6
MC time frame for wound infection, medications
POD 5-7
MC time frame for an abscess to develop
POD 7-10
What organisms can cause a fever in 48 hours?
C. perfringens or group A beta hemolytic strep
Define when a nosocomial infection can occur?
48 hours after admission or up to 30 days after discharge
What % of nosocomial infections can be prevented?
35%
MC nosocomial infection?
UTI
What % of nosocomial UTIs are due to E. coli
80%
What group of pts have the highest risk of developing a nosocomial infect?
Burn patients: UTI, VAP, CRBSI